beta decay of the 5(+) isomer of the odd-odd nucleus Nb-100 - art. no. 014315

The decay of the 3 s isomer of Nb-100 has been investigated by gamma spectr oscopy of online mass separated Nb-100. Several new transitions in the daug hter nucleus Mo-100 have been observed. This results in a more consistent d ecay pattern leading to a firm 5(+) assignment to the Nb-100 isomer. A QRPA based calculation reproduces the decay features best if the pig(9/2)-pip(1 /2) gap is enlarged, confirming the importance of the subshell gap at Z=40 previously introduced to account for low-lying 0(+) states in other N=58 is otones.